With all the knowledge out there I know I will get my answer here. My project involves a 71 Cutlass S with a 350, but I think I have found a donor 68' Delmont 88 with a 455. As far as swapping motors will this work for me and if so should i take the transmission as well. Also what are these 200R and 700R transmissions. thanks

 

It will probably have a TH 400, however it will be a long shaft unit, longer than your stock TH 350. 2004 and 700r are later model overdrive transmissions. The 200 will bolt up, the 700 requires an adapter. Both will cost a fair amount to build up. Unless you are running a bunch of gear, not necessary, IMO. You can build your 350 to last behind either a 455 or 350 for less money.
Engine swap is fairly basic, there will be some minor issues.

 

If you use the 455, don't forget to get the frame mounts.
You could probably find a shorttail 400 turbo on CL for cheap.
I see them all the time. Also get the driveshaft, you will need
the yoke for the 400. I don't know if you can use your 350's
driveshaft though. I think it may be to short, not sure.

 

thanks for the info guys, i did't know that you could still use a 350 tranny behind a 455, i didn't think that it could handle the power.

 

You CAN use it, but you're right, a 350 turbo
won't last behind a 455 unless it is built right.

 

My 77' originally had a 403(small block) in it, and swapped it out to a strongly built 455, years ago. Was really just a drop in, and pretty sure the motor mounts are the same, although I replaced those too. Some of the 403 accessory brackets had to be modified a bit, as the 455 is wider, but I have welding equipment. Also, the drive belts are a bit longer. Took the high tech approach on this. Cut open the 403 belts, wrapped them in position, and measured the difference. Took them to the auto parts store, and said give me one of these, only 2 inches longer. Works fine. While not at first, car now has a 700R4 od tranny, in place of original TH350. As mentioned, the 700R4 is a Chevy bolt pattern, so needed an adapter plate. Also longer than the TH350, so had to get the driveshaft shortened a couple inches, but uses the same slip yoke. The 0.70 4th lock up overdrive, is sure nice for long highway cruises. I'd look pretty close at the Delmonts 455, as some of those were pretty choked down 2 barrel jobs.

 

Is the Delmont trashed beyond saving ?.

Damn shame to yank it's heart out if it's not.

 

A TH350 will handle a stout 455 with no problems IF its in good condition. Install a good shift kit and relax. If it needs rebuilt make sure to to do some internal modification to add reliability.

 

To go back to the tranny issue, IMO use the 200-4r if possible, easy bolt in. You don't need any adapters and your stock th350 driveshaft will slide right in.
Just move the crossmember back to the last set of holes and you're there.
Plus the ratios are a little closer on the 200 vs the 700. And the 200's overdrive is even a little better at .66.

 

NOOOOOO.....

First of all, on a 68 Delmont there are NO frame mounts. The motor mounts have threaded studs that go directly into holes in the crossmember. This mount system only works in 65-70 full size cars.

ONE MORE TIME - please this thread for motor mount info.

https://classicoldsmobile.com/forums...tion-list.html

 

Thanks Joe. And they say you CAN learn something new everyday.
I know I just did...

 

To simplify what Joe is saying for the OP...

Your car is originally a 350 car correct? When you buy new engine mounts for the new engine, buy 350 engine mounts. Everything will line up fine. There is no need to blow $100 on frame mounts.

 

Back to trannies, 2004R or 700R4 od, it's really your choice. 2004R is pretty much a direct drop in, while 700R4/4L60 is a bit more work, but really not much of a deal, if you're good with a wrench. Really couldn't pass on this myself, as was able to get the strongest factory fresh job for a pretty good price. Did put a Trans-Go shift kit in it, but if doing it again, would go 4L60E, as computer controlled, and much easier to dial in. Computers are cheap now, and setting up standard shift point's, TV cables, is a pain. Plus, 700R4/4L60's are much more commonly availible.

 

 

don't know how the car looks, will see it on saturday, has not been started in awhile so i hope that goes well or the search will continue.

 

remember to check for the speedometer input if you decide to go with the th 400, I think the 88 had a wheel mounted speedo input

 

I still don't understand why so many guys feel the need to suggest OD transmissions. A mild 455 with a 3.08-3.23 gear will be great fun to drive and does not require either 200/700 trans. A TH350 can be built a LOT cheaper than either.

 

turned on the printer and let it go now have to get 3 ring binder for all the good reference material. thanks

 

will probably go with the TH400, sounds easy enough.

 

 

helpful,printed and binded.

 

i have read posts about using B-body disc brakes on A-frame cars how and does this work. i want to do disc brake conversion on front, so many choices and i have questions so all your input is great

 

Kind of a no brainer for me. Running a 3.73 posi in my car, and with the 700R4's 3.05 1st gear, thing really move's. The 0.70 od 4th, is like running a 2.56 axle on the highway. Factor in the lock up torque converter for another 200 rpm drop, and why not. Car actually gets pretty good fuel milage, as barely takes any throttle to get it moving, and nice cruising at highway speeds. Since not much more work, rather just go a little more modern. Well worth the effort.